1. Field of the Invention
The present invention relates to a small gas cooking stove which uses a small gas cylinder, which exhibits satisfactory portability and which is capable of heating an object of heating in a relatively short time.
2. Description of the Related Art
A gas cooking stove can easily be carried to an arbitrary site. Moreover, the gas cooking stove permits relatively strong beating power to be obtained. Therefore, the gas cooking stoves are widely used in outdoors as well as in households and cookshops in which the gas cooking stoves are used commercially. A valve mechanism having a stem is mounted on the body of the gas cylinder. The gas cylinder is filled with a liquefied fuel gas, such as liquefied butane or the like, having a relatively low activity. A portion of the liquefied fuel gas enclosed in the body of the gas cylinder is vaporized, causing the internal pressure of the gas cylinder to be higher than the outside pressure. The gas cylinder is joined to the gas cooking stove so that the stem is pushed inwards and the valve mechanism is opened. Thus, the fuel gas is discharged owing to the internal pressure. Note that the gas cylinder for households has a structure that the diameter of the body of the gas cylinder is about 66 mm and the overall length of the same including the stem is about 185 mm.
The gas cooking stove arranged to be used outdoors must have a simple structure, light weight and satisfactory portability. For example, a small gas cooking stove has been disclosed in Japanese Patent No. 2663340 under the title of xe2x80x9cPORTABLE GAS COOKING STOVExe2x80x9d (filed by PEARL METAL Co., Ltd.). The portable gas cooking stove disclosed as described above incorporates a body of the gas cooking stove, a burner, grate and a dish. A gas cylinder directly joined to a joining portion formed in the lower portion of the body of the gas cooking stove serves as a dish for receiving fluid. The portable gas cooking stove disclosed as described above has the grate which is capable of rotating with respect to the body of the gas cooking stove. Thus, the grate is rotated to an arbitrary position when the gas cooking stove is used. The foregoing portable gas cooking stove requires only a small number of elements. Moreover, the size can be reduced when the gas cooking stove is not used by reducing the diameter of the grate. Therefore, the portability can be improved. As a result, the foregoing gas cooking stove is used as significantly advantageous camping equipment.
In general, it is necessary for the gas cooking stove to stably be installed when the gas cooking stove is operated. Moreover, the gas cooking stove must allow an object which must be heated to stably be installed. The foregoing portable gas cooking stove disclosed as described above has the structure that the grate is extended to permit an object, which must be heated, to stably be installed. The portable gas cooking stove disclosed as described above is arranged such that the area for installation is the outer diameter of the gas cylinder. Therefore, there arises a problem in that a large area for installation cannot easily be obtained and, thus, a large object cannot be heated.
Therefore, the portable gas cooking stove is arranged to use a gas cylinder having a large outer diameter with respect to the overall height, that is, a so-called xe2x80x9cshort cylindricalxe2x80x9d shape to obtain the area for installation. The foregoing gas cylinder, however, requires a large space. As a result, the portability deteriorates if the gas cooking stove has a small size and a light weight.
The portable gas cooking stove disclosed above has a structure for directly joining the gas cylinder to the joining portion. The structure, which has not been described in the specification, is arranged such that a thread formed in a cylindrical portion of a mounting cup for joining a valve is used to screw the gas cylinder to the joining portion. Another method has been employed with which an engaging member provided for the joining portion is engaged to a flange portion and the engaging member is rotated. Thus, the gas cylinder is joined to the joining portion. Another method has been employed with which a pipe-shape needle member provided for the joining portion is inserted into a portion of the gas cylinder having a small thickness.
The foregoing screwing method must perform an operation for rotating the gas cylinder in a state in which the joining portion is engaged to the inside portion of the flange portion. Thus, there arises a problem in that a complicated handling operation must be performed. The engaging method using the engaging member encounters a problem in that the structure is too complicated because a plurality of the engaging members and structures for supporting the plural engaging members are provided for the body of the gas cooking stove. Although the needle insertion method is able to improve the operability because the gas cylinder is, by a one-touch manner, joined to the body of the gas cooking stove, there arises a problem in that the needle member will easily be broken. What is worse, an opening formed in the gas cylinder causes a problem to arise in that the gas cylinder cannot again be used.
Another gas cooking stove having a small size has been disclosed. The foregoing gas cooking stove incorporates a grate opening/closing mechanism which incorporates a plurality of support shafts provided for, for example, an outer periphery of the dish so that an end of plate-like grate is rotatively supported by each of the support shaft. Moreover, the foregoing gas cooking stove incorporates a mechanism for opening/closing plate-like support legs each having an end which is rotatively supported by the support shaft. The foregoing gas cooking stove is structured such that each grate member and support leg is rotated in a direction of the tangential line so as to be stopped by a stopper when the gas cooking stove is used. The foregoing gas cooking stove has a characteristic that the multiplicity of the grate members and support legs are folded along the outer surface of the dish and that of the body of the gas cooking stove so that the size reduction is permitted.
However, the multiplicity of the grates and the support legs of the foregoing gas cooking stove must be folded in orderly sequence. That is, a complicated operation must be performed. Another problem arises in that the multiple grates and support legs project outwards even in an accommodated state, thus causing a space efficiency deteriorates. Since the above-mentioned gas cooking stove has the support shafts and stoppers, there arises a problem in that many elements are required and thus the structure cannot be simplified.
A tabletop gas cooking stove having a relatively large size for use in housholds or the like usually has a governor mechanism for controlling the flow rate of a gas. If the internal pressure of the gas cylinder is rapidly raised owing to abnormal heat or the like of the gas cylinder, the governor mechanism also has a safety function to prevent occurrence of a serious accident, such as explosion of the gas cylinder such that the governor mechanism closes the passage for the gas to automatically extinguish the burner. As described above, the tabletop gas cooking stove has been structured such that the governor mechanism is operated to interrupt supply of the gas if the pressure of the gas is raised to a level not lower than a predetermined pressure during a usual state of use. The gas cylinder must conform to a safety standard that the body of the gas cylinder is not deformed when the internal pressure is 13 kgxc2x7fcm2 or lower.
The foregoing governor mechanism causes the size of the gas cooking stove to be enlarged and makes the structure of the same to be complicated. Moreover, the governor mechanism raises the cost of the gas cooking stove. Therefore, the governor mechanism is not usually provided for the foregoing portable gas cooking stove disclosed as described above and having the structure that the gas cylinder is directly connected to the gas cooking stove. The reason for this lies in that the abnormal heat or the like does not easily occur because the foregoing gas cooking stove is usually used outdoors and therefore relatively sufficient heat radiation can be realized.
Since relatively large heating power can be obtained from the gas cooking stove, the gas cooking stove is sometimes substituted for a cooking range using solid fuel and serving as an apparatus for heating a cooking pan or meat. Since a gas cooking stove for households is employed as the foregoing gas cooking stove, there arises a problem in that the size of the gas cooking stove for households is too large to be placed on a table while permitting other dishes to be placed on the same table.
The applicant of the present invention has provided a new and very-small gas cylinder having an outer diameter of about 35 mm, a height to the leading end of the stem is about 53 mm and weight of about 26 g and filled with about 12 g of liquefied fuel gas. The new gas cylinder filled with the liquefied fuel gas in a quantity which is sufficiently large to perform cooking for one person enables a gas cooking stove to be realized which has a small size and satisfactory portability and which is capable of efficiently using a limited space on the table.
Accordingly, an object of the present invention is to provide a small-size gas cooking stove which is adaptable to the foregoing very-small gas cylinder arranged to be, in a one-touch manner, joined/removed to a portion of the gas cooking stove for joining the gas cylinder, capable of reliably maintaining the state of joining, which can stably be installed when a cooking operation is performed and reducing the size when the apparatus is not used to efficiently use a space, which can easily be operated and which exhibits satisfactory safety and portability.
To achieve the foregoing object, according to one aspect of the present invention, there is provided a gas cooking stove arranged to use a gas cylinder having a valve-joining cylindrical portion which is molded integrally with the upper portion of the body of the gas cylinder to project over the upper portion of the body, which fixedly accommodates a valve mechanism and which has a projecting stem. The gas cooking stove according to the present invention comprises: a dish provided with a burner and a grate so that a combustion portion is constituted. The gas cooking stove incorporates a body, which is provided with a valve mechanism for supplying fuel gas to the burner and an operating member for opening/closing the valve mechanism, and which has an upper portion to which the dish is joined and a lower portion provided with a gas-cylinder joining portion to which the gas cylinder is joined.
The gas-cylinder joining portion has an engaging recess having a gas passage allowed to communicate with a valve hole which supplies fuel gas to the valve mechanism through the burner and a cylinder holding mechanism for holding the valve-joining cylindrical portion of the engaged gas cylinder.
The gas-cylinder joining portion incorporates a cylinder-holding-member joining portion having an annular shape and formed in the inner surface of the opening formed in the engaging recess of the gas-cylinder joining portion and a cylinder holding member which is formed into a U-like shape and which is made of an elastic member and joined in the cylinder holding member joining portion such that at least a portion of the elastic member projects into the opening.
The gas cylinder is directly joined to the gas cooking stove such that the valve-joining cylindrical portion is inwards pushed into the engaging recess of the gas-cylinder joining portion. The valve-joining cylindrical portion of the gas cooking stove engaged to the engaging recess is held by the cylinder holding mechanism. Fuel gas is supplied into the gas passage of the gas cooking stove through the opening when the stem is inwards pushed in the foregoing state. The operating member is operated to open the valve mechanism, followed by operating the spark plug in a state in which fuel gas has been supplied to the burner. Thus, the fuel gas is burnt.
When the valve-joining cylindrical portion of the gas cylinder is inwards pushed and engaged to the engaging recess of the gas cooking stove through the opening, the valve-joining cylindrical portion is introduced into the engaging recess while the valve-joining cylindrical portion is enlarging the diameter of the cylinder holding member. When the valve-joining cylindrical portion of the gas cylinder is engaged to a position at which a crimping recess formed in the outer surface of the valve-joining cylindrical portion corresponds to the cylinder holding member, the cylinder holding member is engaged to the crimping recess in a state in which the cylinder holding member has elastically been deformed. Thus, the gas cylinder is joined and held by the gas-cylinder joining portion. The gas cylinder can be joined to the gas cooking stove by a one-touch operation that the valve-joining cylindrical portion is inwards pushed and engaged to the engaging recess. When the valve-joining cylindrical portion is drawn from the engaging recess of the gas cooking stove, the diameter of the cylinder holding member is enlarged. Thus, the gas cylinder can be removed by the one-touch operation.
Other objects, features and advantages of the invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings.